Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/02—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by the reacting monomers or modifying agents during the preparation or modification of macromolecules
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/06—Preparatory processes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/22—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen
  • C08G77/24—Polysiloxanes containing silicon bound to organic groups containing atoms other than carbon, hydrogen and oxygen halogen-containing groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
  • C08J2383/04—Polysiloxanes

Definitions

• EP 0 416 229 A2 discloses a method for producing a fine-pored, soft-elastic sealing foam for cover, housing and cavity seals, in which the foam reaction components are processed by means of a low-pressure two-component mixing and metering system and in the free-foaming process without Heat supply to be foamed, the one reaction component containing a silicone polymer with at least two double bonds in the molecule, preferably vinyl groups, an organic platinum catalyst and optionally further additives, while the other component is formed by siloxane as a crosslinker, the ion mixture as additional crosslinking - And blowing agent water is added in a small amount. The addition of water causes the hydrogen siloxane to be reacted almost completely when the silicone composition is foamed, so that a high hydrogen blowing effect is established and the after-reaction with harmful effects on the quality of the silicone foam is avoided.
• the invention is based on silicone compositions in which water is used as blowing agent and hydrogen siloxane is used as crosslinking component. It is the object of the invention to produce a high-quality and fine-pored silicone foam in a process which is easy to control in operational terms from a two-component addition-crosslinking silicone system with an extended pot life or processing time (modified LSR quality) inexpensive to manufacture, preferably in the form of foam sheets, which can be used in a variety of ways in practice.
• Components A and B of the following composition are preferably used in the process according to the invention:
• Component A 100 g Silicone polymer with at least two double bonds per molecule, preferably vinyl groups 0.2-5 g organic platinum catalyst, complexed with butinol, 5-40 g fumed silica, 0.05-5 g Water, optionally further additives, individually or in combination, such as, in particular, color pigment (for example carbon black, iron oxide red), foam regulators (for example fluorosurfactants), flame retardants and fillers (for example quartz powder).
• Component B 100 g Silicone polymer with at least two double bonds per molecule, preferably vinyl groups, 5-40 g fumed silica, 3-20 g Polydimethylhydrogensiloxane (SiH crosslinker)
• the aforementioned components A and B can be processed in a mixing ratio of 1: 1 and have a pot life of at least three days at 20 ° C with this mixing ratio.
• the viscosity of the two components is around 100,000 mPa.s.
• Fluorosilicone polymer can advantageously be used as the silicone polymer for both components A and B.
• the processing of the highly viscous silicone mass takes place in the viscosity range from 30,000 to 500,000 mPa.s, whereby a high-quality, mechanically resilient silicone foam can be obtained.
• the reaction mixture subjected to the pressurized gas over a longer period of several hours contains the gas finely divided in dissolved form, so that it can be effective in the subsequent foaming reaction for nucleation.
• compressed air or compressed nitrogen is preferably used as the compressed gas, although other gases, such as noble gases in particular, can also be used. Without the absorption of the dissolved gas in the reaction mixture, there would be no foaming reaction with the desired fine-pored foam formation.
• the reaction mixture mixed with the dissolved gas is expediently foamed in the area application.
• the heating of the reaction mixture necessary for the foaming process can advantageously be carried out by passing through a continuous furnace or the like. respectively.
• the two components A and B mentioned are expediently prepared so that they are each free of air bubbles. They are mixed appropriately before the pressurized gas is applied so that there are no inclusions of air bubbles in the mixture. This can be done by static mixing in the absence of air, e.g. when passing through a mixing tube, a mixing screw or the like. Does the silicone mass contain air bubbles, e.g. by simply stirring the two components A and B in an open mixing vessel, a more or less blistered or perforated silicone foam is formed which is unsuitable for the various purposes.
• the absorption of dissolved air (or another gas) without the presence of air bubbles in the reaction mixture guarantees the development of a high-quality silicone foam with high fine-celledness and uniformity.
• reaction mixture produced from the two components contains air bubble inclusions, it is recommended therefore, vent the mixture before applying compressed gas by vacuum treatment.
• the reaction mixture which is free of air bubble inclusions but mixed with the dissolved gas, is expediently applied with the desired layer thickness in a doctor blade or brush method, it being heated, for example, to a temperature of 150 ° -220 ° C. in a continuous furnace.
• the foaming and solidification reaction then takes place within about 0.5 to 5 minutes, depending on the layer thickness of the reaction mixture and on the nature of the base body carrying it. Since hydrogen is released during the foaming process by chemical reaction, it is advisable to use a continuous dryer or continuous oven with a fresh air recirculation control that can be controlled by hydrogen detectors.
• the reaction mixture can also be applied to a base such as, in particular, a metal sheet, a metal foil, for example an aluminum foil, on a fabric tape, for example PTFE fabric tape, and brought to foaming, an adhesion promoter (silane adhesion promoter) being able to be used if necessary to get a firm bond of the silicone foam of the underlay.
• a base such as, in particular, a metal sheet, a metal foil, for example an aluminum foil, on a fabric tape, for example PTFE fabric tape, and brought to foaming, an adhesion promoter (silane adhesion promoter) being able to be used if necessary to get a firm bond of the silicone foam of the underlay.
• the silicone foam can also advantageously be processed to form a foam sheet which can expediently be wound up into a roll by inserting a separating film.
• the usual layer thicknesses of the silicone foam are 2 - 30 mm.
• the bulk density of the silicone foam is generally 0.2-0.8
• silicone foam produced by the process according to the invention for example wound up into a roll or cut into blocks
• high-quality seals can be used, for example, by lamination with aluminum foil heat shields or by lamination with flexible fabric, inner inserts for clothing, in particular for surfing or diving suits and the like. produce.
• Silicone foam can be used for many other purposes due to its high foam quality and its inexpensive production method. It is also possible to laminate the silicone foams or silicone foam sheets produced by the process according to the invention on both sides.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Silicon Polymers (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=25919700

Family Applications (1)

Country Status (6)

Families Citing this family (17)

Family Cites Families (12)

• 1992
  • 1992-10-22 DE DE4235638A patent/DE4235638A1/de not_active Withdrawn
• 1993
  • 1993-07-30 EP EP93112212A patent/EP0593864B1/de not_active Expired - Lifetime
  • 1993-07-30 DK DK93112212.1T patent/DK0593864T3/da active
  • 1993-07-30 AT AT93112212T patent/ATE159964T1/de not_active IP Right Cessation
  • 1993-07-30 DE DE59307639T patent/DE59307639D1/de not_active Expired - Fee Related
  • 1993-07-30 ES ES93112212T patent/ES2110548T3/es not_active Expired - Lifetime
  • 1993-10-22 US US08/141,299 patent/US5356940A/en not_active Ceased

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